[FFmpeg-trac] #7484(avcodec:new): av_packet_ref(): Allocates array on zero src size

[FFmpeg]

#7484: av_packet_ref(): Allocates array on zero src size
------------------------------------+-----------------------------------
             Reporter:  zerodefect  |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avcodec
              Version:              |               Resolution:
             Keywords:              |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
------------------------------------+-----------------------------------

Comment (by zerodefect):

 I took a stab at this over the end-of-year break.  I think the best way to
 solve this is to disable allocation of an AVPacket with size of 0:

 {{{
 diff --git a/libavcodec/avpacket.c b/libavcodec/avpacket.c
 index e160ad3033..df4cafc6da 100644
 --- a/libavcodec/avpacket.c
 +++ b/libavcodec/avpacket.c
 @@ -71,7 +71,7 @@ void av_packet_free(AVPacket **pkt)
  static int packet_alloc(AVBufferRef **buf, int size)
  {
      int ret;
 -    if (size < 0 || size >= INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
 +    if (size <= 0 || size >= INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE)
          return AVERROR(EINVAL);

      ret = av_buffer_realloc(buf, size + AV_INPUT_BUFFER_PADDING_SIZE);

 }}}


 I applied the above patch to latest.

 As per the development guidelines, I tried out the fate suite of tests,
 but I notice that the `acodec-flac` test fails which could be bad. I tried
 to follow the make file, but I struggled to quite understand how fate
 works in order to debug.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/7484#comment:1>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker